The invention relates to applying an extension force to a phalangeal deformity.
Phalangeal deformities occur in fingers and toes. In fingers, one such deformity is referred to as a “boutonniere deformity.” In toes, one such deformity is referred to as a “hammer toe.”
Boutonniere deformities occur in fingers and consist of a proximal interphalangeal joint that is flexed and a distal interphalangeal joint that is hyperextended. This deformity makes it difficult or impossible to extend the proximal interphalangeal joint. It is commonly caused by injury or by an inflammatory condition like rheumatoid arthritis.
A pseudoboutonniere deformity is a condition marked by proximal interphalangeal joint flexion contracture and restricted flexion of the distal interphalangeal joint. The characteristic hyperextension of the distal interphalangeal in boutonniere deformities is not present in pseudoboutonniere deformities.
Ring splints have been developed to straighten or realign interphalangeal joints of fingers and thumbs. One such ring splint includes two elliptical rings joined by an elliptical spacer as described in U.S. Pat. No. 4,932,396. The ring splint disclosed in U.S. Pat. No. 4,932,396 is described as being worn with the spacer over the joint on a boutonniere finger or mallet finger. In such a position, the ring splint is described as being capable of holding the finger in extension.
Hammer toe is a deformity of the toe in which the end of the toe bends downward in a claw-like position. Hammer toe affects the proximal interphalangeal joint of the toes. Mallet toe is also a deformity of the toe that affects the distal interphalangeal joint. Claw toe, another deformity of the toe, is the presence of dorsiflexion of the proximal phalanx on the lesser metatarsophalangeal in combination with flexion of both the proximal and distal interphalangeal joints.
There are various ways that one can attempt to address toe deformities including wearing the proper size shoes and avoiding wearing high heels. In severe cases surgery is necessary to correct the deformity. The surgery can involve cutting or moving tendons and ligaments. Sometimes the bones on each side of the joint need to be connected (fused) together.